Coating composition



Patented Dec. 30, 1941 COATING COMPO SITION George D. Martin, Nitro, W. Va., assignor to Monsanto Chemical Company, St. Louis, Mo.,a corporation of Delaware No Drawing. Application .Ianuary 9, 1939, Serial No. 249,849

12 Claims.

The present invention relates to a coating composition and more particularly to a coating composition containing a drying oil, for example paint, varnish, enamel, linoleum and the like.

It is the usual practice in the manufacture of coating compositions containing drying oils to incorporate a positive oxidation catalyst which usually consists of a heavy metal salt such as a a salt of cobalt, iron, manganese or lead. This positive oxidation catalyst is commonly referred to as a drier and imparts certain beneficial properties, as for instance hastening the formation of a hard, dry film. The drier likewise has certain objectionable properties. Thus the oxidation once initiated may continue too far or an oxidation may take place in the bulk state with the formation of a film or skin on the surface during storage, etc.

The tendency of a paint to skin is particularly noticeable in the presence of certain pigments and in paint containing appreciable quantities of China-wood oil or polymerized linseed oil. This property eliminates from commercial use certain compositions which possess otherwise de-' sirable features. The prevention of skinning is an important problem in dipping operations where the paint is necessarily exposed to the oxidizing influence of the atmosphere for extended periods of time.

It is thus desirable to inhibit the oxidation of drying oil compositions sufiiciently to prevent skinning during manufacture, during dipping operations and during storage. formed, however, the beneficial action of a drier in forming a hard dry film in a short time must preferably be unimpaired without however a continued oxidation resulting in subsequent deterioration and cracking. The highly selective action required of an anti-skinning agent is thus evident.

It is an object of the present invention to provide a drying oil composition of improved properties.

Another object is to provide a drying oil composition of improved resistance to skinning in bulk or in the container.

A further object is to provide a coating composition comprising a drying oil and possessing improved properties.

A still further object is to provide a class of materials which substantially prevent undesirable oxidation of the drying oil composition. Other objects will be hereinafter shown.

In accordance with the present invention it has been discovered that esters of trivalent phosphorus acids are important and desirable adjuvants to drying oil coating compositions. These products, in general, are obtainable by reacting a phenol or alcohol or mixtures thereof with a trivalent phosphorus compound capable of form- Once a film is' in'g'an ester, as for example a phosphorus tri halide. By this means a mono or dihalogen containing ester is'obtainable as well as the neutral ester resulting from complete replacement of the halogen. Halogen and halogen free acid esters as well as neutral esters of trivalent phosphorus acids have been found to be effective antiskinning agents and are included Within the scope of the present invention.

An example of a typical preparation is that of para hydroxy phenyl phosphorous acid dichloride. Substantially equimolecular proportions of hydroquinone and phosphorus trichloride were reacted in the presence of 'a suitable inert organic solvent, for example ether. After isolation of the product by suitable means, it was analyzed for, phosphorus and found to contain 14.6% phosphorus. The calculated value for para hydroxy phenyl phosphorous acid dichloride,

01 O no- 0-? is 14.7% phosphorus. As a further typical example of the invention, the monochloride was prepared from the above product by partial hydrolysis. The product obtained was found upon analysis to contain 15.9% phosphorus. The calculated value for p-hydroxy phenyl-phosphorous acid mono chloride,

which was then reacted with catechol to produce one of the preferred class of materials by the replacement of the halogen atoms with an ortho phenylene group as follows o-phenylene p-tolyl phosphinous acid The present invention does not relate to the preparation of the preferred materials nor is it limited thereto. Esters of phosphorous acids likewise halogen, OH, OR or R B. being an aryl or alkyl group and in addition may be O attached to R. l

Other typical examples of the preferred class of materials according to the invention comprise o-phenylene phosphorous acid chloride p-hydroxy phenyl o-phenylene phosphite 0 l [l P O OH o-chlor phenyl o-phenylene phosphite p-tolyl o-phenylene phosphite o ,B-naphthyl phosphorous acid dichloride diamyl, p-hydroxy phenyl phosphorous acid dichloride C5Hu p-tolyl phosphorous acid dichloride CHs-O-O- P/ c1 chlor phenyl phosphorous acid dichloride \C1 01 di chlorphenyl phosphorous acid monochloride o-1 o- Q o? (J1 o1 di-p-tolyl phosphorous acid monochloride omG-o-r-o-O-cm t1 the salicylic acid ester of phosphorous acid monochloride of the formula, according to R. Anschutz and W. Emery (Ann, 239, p. 304), of

p-phenylene di(phosphorous acid dichloride) o-phenylene phosphite butyl o-phenylene phosphite o-diphenyl phosphorous acid dichloride 5 hydroxy 1 naphthyl phosphorous acid [3 naphthyl phosphorous acid p-tolyl phosphorous acid p-diphenyl phosphorous acid H p-hydroxy phenyl o-phenylene phosphite and dibutyl p-hydroxy phenyl phosphite O C4Ho As one method of operating the present invention, portions of a paint, varnish or enamel,

which readily skins on contact with the air, were placed in suitable containers, 2. small proportion of one of the new class of anti-skinning agents incorporated therein and observations made at regular intervals as to the skinning of the composition, whereby it was found that the new and preferred class of anti-skinning agents prevented the formation of a skin for extended periods of time.

As a specific embodiment of the present invention grams of a quick drying enamel comprising a gallon China wood oil varnish containing 2.5% of a mixed lead manganese and cobalt dryer was placed in a wide mouth open container of 50 c. c. capacity. 20 milligrams of anti-skinning agent was incorporated therein and a comparison made as to the skinning time of the same enamel containing no inhibitor of skin formation, a temperature of 25 C. being maintained throughout the test. Typical results from a series of such tests are given in Table I.

Table I I Concen- Days before Anti-skinning agent tration formation of employed skin Per cent Blank None 1 p-Hydroxy ph yl phosphorous acid dichloride 0. l 13 p-Hydroxy phenyl phosphorous acid monochloride 0. 1 l5 o-Phenylene phosphorous acid chloride" 0.1 16 Di chlorphenyl phosphorous acid chloride 0. 1 15 Table II Conccn- Days before Anti-skinning agent tration formation of employed skin Per cent Blank None 1 Butyl o-phenylene ph0sphite 0. 1 44 o-Phenylene phosphite- 0. l Tolyl o-phenylene phosphite 0. l 31 o-Ohlor phenyl o-phenylene .phOSphlHL 0. l 40 The above data show that the compounds of the present invention as exemplified by the neutral esters of trivalent phosphorus acids are excellent anti-skinning agents.

The present invention is not limited to the specific examples herein given to illustrate the invention. Other and further members of the new class of anti-skinning agents may be incorporated in a drying oil composition thereby effecting desirable improvements. For example diamyl p-hydroxy phenyl phosphorus acid dichloride and meta hydroxy phenyl phosphorus acid dichloride were tested in the manner hereinbefore described and found to inhibit the formation of a skin for 8 and 6 days respectively whereas without an inhibitor of skin formation a thick skin formed in one day.

Likewise other methods of testing the preferred materials may be employed and other means may be utilized to show their desirable properties. For example instead of carrying out the tests in open containers, tests may be run employing closed containers so as to more nearly approximate the conditions met with in coating compositions put up in sealed containers for storage and distribution. The desirable properties of the preferred materials were readily shown upon test.- ing the preferred materials in this manner. For example 5 hydroxy 1 naphthyl phosphorous acid and o-phenylene p-tolyl phosphinous acid prevented the formation of a skin for 30 days and 32 days respectively when tested by the closed container method whereas a blank, that is the same drying oil composition, in a closed container, but to which no inhibitor of skin formation was added, formed a thick skin in two days. Di butyl para hydroxy phenyl phosphite and o-phenylene p-hydroxy phenyl phosphite gave very, exceptional results when tested in this manner, preventing the formation of skin for many months.

While the amount of preferred class of materials employed in the specific embodiments of the invention as set forth above is 0.1% based on the weight of the total drying oil composition, the quantities employed may be varied depending on the specific composition of the coating material. Generally it is found that less than 1% of the preferred material will be sufiicient. Ordinarily 0.05 to 0.50% is sufficient. It is obvious that the processes and compositions described herein may be varied widely in their details without departing from the spirit or scope of the present invention. The present invention is limited solely by the appended claims.

What is claimed is:

1. A coating composition containing a drying oil of the type which rapidly develops a skin in bulk condition having incorporated therein a positive oxidation catalyst and a controller of oxidation comprising an ester of a trivalent phosphorus acid wherein at least one of the ester forming groups is an aryl or arylene group.

2. A coating composition containing a drying oil of the type which rapidly develops a skin in bulk condition having incorporated therein a positive oxidation catalyst and a controller of oxidation comprising a compound possessing the structure where R is an aromatic carbocyclic radical and a: is a member of a group consisting of halogen, OH, OH or R and y which may be the same or different than at, is a member of a group consisting of halogen, OH, OR or R, R being a member of a group consisting of aryl groups which may be substituted and alkyl groups, and in addition y may be O- attached to R.

3. A coating composition containing a drying oil of the type which rapidly develops a skin in bulk condition having incorporated therein a positive oxidation catalyst and a controller of oxidation comprising a compound possessing the structure where R is an arylene radical and x is selected i.i,i2,268,491,,./

= om e mup w fis o halo en; 01 9 5 1" i f 011 of the 2 type whicihi rapidly deveicp's' a; serum; 2 I i i jferent thanfl y a a A coating compos tion containing a dry oil of the type which rapidly: develops: a skinz in positive oxidation catalyst and a controller :of

zoxidation wmpjrisin a compo nri possessing the f bulk condition: having :incorportaed therein a 1 positive oxidation catalyst and a cont-smile]: or: 1

, i 1 L a l i oxidation. comprising; an ester of phosphorous: v v l eie z m i t e e z n an na th l n s ri s: 5- A? ati eomposition c n a ni a dr n oil of I th t p which rapidly develops a; skin :in:

bu b n i i n I h v n in o po ated: therem a i 11, A coating composition containing a dry oil; of 3 the type which rapidly eg/B ess a? skin ujlki I condition havine incorporated ther'em' a :positive oxidation catalyst and? a coi'it'ro'lier of oxidation comprising a compound; possessing; the I strnctiire' oil of the: typewhich rapidly; develops a skin in; I I 1 bulk-conditionhaving-incorporated :therein a i w =positive oxidation-catalystand a controller of l' qoxidation comprising; an: ortho phenylene ester" oxidation comprising; :a; nbstantiall irit loph nyle ephos hite-1, mu r i ine icog pe i nn: cont i in a; d ym I of thedyne hich; rapidly; develops; a skin; in .uik' conditi 1 13 h vine; incorporated; therein I *o 5 xi a i n i a alyst ian'cl a "controiier f of v I I 1 g oi or theztyp whic ap diyi deviops' a =51; 11 buiki condition; havmgiinco orated therein a positive i oxidation? catalyst? iafnfd T a controil e oxidation comprising compoun possessing oxidation 'eorrnorising=:oli:Joutyl::para l'iydrox w=' y.;: :y;: 1; p9;Aroatingcomposition containingadrying P .7 oil ofthetypewhichrapidIydevelops-a-skinin:= I I I i a I 1 1 j huik: condition havingi incorporated therein a wherein 'R is a phenyle'ne radian; R is an 'aryr I I a I 1 3 positive oxidation catalyst and a controller of radical of the benzene series and a: is an integer oxidation comprising o-phenylene phosphite. less than three.

10. A coating composition containing a drying GEORGE D. MARTIN. 

